Manufacture of butanedicarboxylic acid esters

Abstract

Deactivated cobalt catalyst from the carboxalkoxylation of butadiene is regenerated by contact with a strong acid ion exchange resin.

We claim: 
     
       1. A process for the preparation of dialkyl butanedicarboxylic acid esters which comprises initially reacting a mixture comprising a compound selected from the class consisting of butadiene, carboalkoxylation products of butadiene and mixtures of the foregoing with carbon monoxide and a lower alkyl alcohol in the presence of a cobalt-containing catalyst and tertiary nitrogen base at temperatures in the range 80°-200° C. and pressures in the range 100-2000 atmospheres to obtain a reaction product, contacting at least a portion of the reaction product with a strongly acidic ion exchange resin and returning at least a portion of the thus treated material to the initial reaction. 
     
     
       2. The process of claim 1 wherein the tertiary nitrogen base is pyridine. 
     
     
       3. The process of claim 1 wherein the strongly acid ion exchange resin comprises a styrene-divinylbenzene copolymer substituted with sulfonic acid groups. 
     
     
       4. The process of claim 3 wherein the tertiary nitrogen base is pyridine. 
     
     
       5. The process of claim 4 wherein the lower alkyl alcohol is methanol.